1. Field of the Invention
The invention generally relates to roll film holders and to roll film cameras. More particularly, the invention relates to a multi-format camera for taking different size pictures on separate rolls of film and to roll film holders having respective metering mechanisms for advancing the film in different length increments to enable multi-format use of the camera.
2. Description of the Prior Art
Roll (non-perforated) film is backed with an opaque paper strip which has printed numbers corresponding to the number of negative spaces on the film. The most popular roll film, probably size 120 film, is approximately 2.45 ins. (6.22 cm.) wide. The backing paper on size 120 film has several series of numbers. A first series is numbered proximate one longitudinal edge of the paper to give 16 exposures to the roll measuring 21/4.times.1 5/8 ins. (6.times.4.5 cm.). Another series is numbered along the longitudinal center of the paper to give 12 exposures measuring 21/4.times.21/4 ins. 6.times.6 cm.). A third series is numbered proximate the other longitudinal edge of the paper to give 8 exposures measuring 1/4.times.31/4 ins.(6.times.9 cm.). A fourth useful possibility, which is not numbered on the paper, is 10 exposures to the roll measuring 21/4.times.23/4 ins. (6.times.7 cm.).
Roll film cameras equipped to take pictures in two or more of the different sizes, i.e., 21/4.times.15/8 ins., 21/4.times.21/4 ins., 21/4.times.31/4 ins., and 21/4.times.23/4 ins., on separate rolls of film having the same length and width, are referred to as multi-format cameras. Many of these cameras are used with several roll film holders for taking the respective size pictures. To take pictures in a different size, the roll film holder being used must be removed from the camera and replaced by a film holder corresponding to the desired picture size.
In a multi-format camera, the film metering, that is, the length of film travel between successive exposures, differs in accordance with the format, i.e., the picture size, being used. Thus, when changing the roll film holder in the camera to take pictures in a different size, the metering mechanism or the drive for such mechanism must be altered to change the length of film travel to accomodate the desired picture size.
One proposed solution to the problem of providing for different film metering in a multiformat camera is described in U.S. Pat. No. 2,926,424. That solution involves the use of interchangeable metering units for advancing roll film in different length increments. One metering unit is taken out of the camera and replaced by a different metering unit, to change to the length of film travel required for taking pictures in a different size. Another proposed solution which is described in the same patent attacks the problem from a different approach by employing a single, permanent metering unit for the different picture sizes. That solution involves the use of a manually shiftable transmission for driving the metering unit to provide the different lengths of film travel required for the different picture sizes.
Although the proposed solutions in U.S. Pat. No. 2,926,424 to the problem of providing different film metering in a multi-format camera may accomplish their intended purpose, they have several drawbacks. For example, each time a change in the picture size is desired, there must be an exchange of interchangeable metering units in the camera before an exchange of film holders can be completed. Alternatively, the photographer must remember to operate the shiftable transmission for the permanent metering unit.